2-Ethylhexanol induces autism-like neurobehavior and neurodevelopmental disorders in zebrafish

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impaired social interaction, communication deficits, and repetitive behaviors. The rising prevalence of ASD necessitates intensified research. 2-Ethylhexanol, is a synthetically produced branched-chain alcohol used in plasticizer synthesis. However, its role in ASD-like symptoms and potential neurotoxic effects remains largely unexplored. This study employed a multimodal neurotoxicity testing approach to evaluate the adverse effects of 2-ethylhexanol on zebrafish neurobehavior and neurodevelopment. Wild-type and transgenic zebrafish lines (tg(elavl3: eGFP) and tg(mbp:mGFP)) were exposed to 2-ethylhexanol for 120 hours post-fertilization (hpf). Significant disruptions were observed in early motor activities, such as tail coiling and touch-evoked responses, which aligned with later locomotor impairments, including reduced distance traveled and increased turn angle. These behavioral changes were accompanied by decreased levels of acetylcholinesterase (AChE) and dopamine (DA). Deficits in social behavior (e.g., reduced body contact) were identified, potentially linked to altered transcription of autism-associated genes (adsl, eif4a1, mbd5, vps13b, and tsc1b). Abnormalities in neurogenesis, including reduced brain and spinal cord size, and demyelination of oligodendrocytes and Schwann cells, were evident. Additionally, transcriptional changes related to neurodevelopment (gap43, manf, sox2) and neurotransmitter signaling (drd1, mao, htr1bd) were observed. Our findings provide compelling evidence that 2-ethylhexanol exposure leads to neurodevelopmental impairments and behavioral alterations reminiscent of ASD. This research highlights the importance of further investigations to assess the potential risks of 2-ethylhexanol exposure and develop prevention and mitigation strategies.